Why don't Christians observe/Celebrate Easter, or Ressurectuon Sunday, after or during Jewish Passover?

Easter is a movable feast: Easter and the holidays that are related to it are moveable feasts which do not fall on a fixed date in the Gregorian or Julian calendars which follow only the cycle of the sun; rather, its date is determined on a lunisolar calendar similar to the Hebrew calendar. The First Council of Nicaea (325) established two rules, independence of the Jewish calendar and worldwide uniformity, which were the only rules for Easter explicitly laid down by the council. No details for the computation were specified; these were worked out in practice, a process that took centuries and generated a number of controversies. It has come to be the first Sunday after the ecclesiastical full moon that occurs on or soonest after 21 March,[10] but calculations vary in East and West. Source: Wikipedia

Because holidays often are random to suit whomever deems the best day. In America we celebrate many holidays on Monday to create a three day weekend. Good Friday weekend works out nicely for a three day weekend too come to think of it. As @jca‘s answer points out, the Easter holiday was planned to specifically ignore the Jewish calendar.

I find it interesting though, that it still is during the same time of the year as Passover. I’ve always thought Christmas being on the 25th of December and Chanukah being on the 25th day of Kislev might. It be a coincidence. Although, Chanukah was not a big holiday 100+ years ago. I know Christmas was supposedly tied in with Yule and Pagan winter celebrations, but I never hear about a possible relationship to the Jewish holiday regarding the date.

Most years, Christians do. But the Hebrew calendar does things like throw in a Leap Month, as they do this year.

Since Sunday Mass is a celebration of both the Last Supper and the Resurrection, and the day for all celebrations in the Church calendar except Christmas, it made liturgical sense to celebrate the Triduum on Thursday, Friday, and Saturday night/Sunday morning.

The connection to the Hebrew calendar is maintained by the basing it on the Sunday after the first full moon of Spring.

(The Eastern Orthodox Calendar is out of sync with the natural world, I can’t speak for when they celebrate anything.)

Passover was an event for Hebrews or better known as Jews, Resurrection Sunday is an event for Christians (even if some have no real understanding of the significances of it).

Same reason most Christians hold the Sabbath on Sunday instead of sundown Friday to sundown Saturday – they evidently decided that God got it wrong.

^ Redacted

Oh stop being a baby and say what you want to say. If it’s unpopular so be it, but at least have backbone enough to say what you mean and to stand behind it.